Problem D
Herman
The 19th century German mathematician Hermann Minkowski
investigated a non-Euclidian geometry, called the taxicab
geometry. In taxicab geometry the distance between two points
All other definitions are the same as in Euclidian geometry, including that of a circle:
A circle is the set of all points in a plane at a fixed distance (the radius) from a fixed point (the centre of the circle).
We are interested in the difference of the areas of two
circles with radius
Input
The first and only line of input will contain the radius
Output
On the first line you should output the area of a circle
with radius
Note: Outputs within
Sample Input 1 | Sample Output 1 |
---|---|
1 |
3.141593 2.000000 |
Sample Input 2 | Sample Output 2 |
---|---|
21 |
1385.442360 882.000000 |
Sample Input 3 | Sample Output 3 |
---|---|
42 |
5541.769441 3528.000000 |